The modern communications era has brought about a tremendous expansion of communication networks. Communication service providers and device manufacturers are continually challenged to deliver value and convenience to consumers by, for example, providing compelling network services, applications, and content. The developments of communication technologies have contributed to an insatiable desire for new functionality. Portable communication apparatuses (for example, mobile phones) are no longer just tasked with making telephone calls. They have become integral, and in some cases essential, tools for managing the professional and/or personal life of users. Recently, Location Based Service (LBS) becomes more and more popular. With the prevalence of LBSs, good privacy protection plays an important role in personal location management and services.